английский => русский Наука Физика symmetry, particel physics, fields

... violation of symmetry arises whenever what was thought to be a non-observable turns out to be actually an observable... The notable examples of such discoveries are the asymmetry of physical laws under the right-left mirror transformation, the particle-antiparticle conjugation and the change in the direction of time flow, past to future and future to past. It turns out that all these supposed non-observables can actually be observed.
T.D. Lee , Particle Physics and Introduction to Field Theory